1. Field of the Invention
The present invention relates to inkjet printers.
2. Description of the Related Art
Inkjet printers are well known to include an ink head having a plurality of nozzles to perform predetermined printing operations on a recording medium by an inkjet technique. Such an inkjet printer is provided with a capping unit for enabling the nozzles to eject ink appropriately. The capping unit has a cap for covering a nozzle surface containing the nozzles when printing is not performed.
The capping unit forms a sealed space by covering the nozzle surface with the cap. By operating a suction pump connected to the capping unit under the condition where the sealed space is formed, ink with an increased viscosity is forcibly sucked out of the nozzles. That is, the ink is forcibly discharged from the nozzles (hereinafter this operation is also called a “suction operation”). This can prevent clogging of the nozzles.
For example, JP 2010-30061 A discloses an inkjet printer in which a nozzle surface is covered by a cap with the nozzle surface being pressed upward by moving the cap upward. In the example shown in JP 2010-30061 A, the cap is attached to the ink head appropriately because a constant force is applied from the cap to the nozzle surface.
In the inkjet printer disclosed in JP 2010-30061 A, the carriage on which the ink head is mounted is configured to be capable of shifting vertically with respect to a first guide member and a second guide member that support the carriage. When performing a printing operation on a recording medium, the carriage is shifted downward to shorten the distance between the ink head and the recording medium. Here, in order to perform high-quality printing, it is necessary to keep the distance constant between the ink head and the recording medium during printing. The carriage that mounts the ink head disclosed in JP 2010-30061 A is, however, not supported on the first guide member and the second guide member in a vertically immovable manner. This means that the carriage can shift vertically relative to the guide rails if vibrations occur in the inkjet printer or the carriage itself moves at high speed during printing. If the carriage can shift vertically, it is impossible to keep the distance constant between the recording medium and the ink head, which is mounted on the carriage, degrading the quality of printing.